Stocks: Five things to know before the open

Can U.S. markets end the week with another record close?

Stock futures were flat early Friday in the absence of obvious market catalysts. But here are five things you need to know before the opening bell rings in New York:

1. More M&A moves: Ireland-based Shire(SHPG) has rejected an unsolicited bid worth about $46 billion from AbbVie(ABBV), saying it undervalued the company and carried significant risks because AbbVie is looking to move its tax base to the U.K. Shire shares gained 11%.

Siemens(SIEGY) and Mitsubishi Heavy Industries(MHVYF) have raised their joint offer for Alstom's energy business, a day after General Electric(GE) sweetened its own bid. France's Alstom has until Monday to choose.

2. European exchange operator falls: Shares in Euronext, the operator of markets in Paris, Amsterdam, Brussels and Lisbon, slipped on their debut after parent company Intercontinental Exchange (ICE) priced its IPO at €20 per share, the lower end of the expected range. ICE also owns the New York Stock Exchange.

3.The rich are worried: A comprehensive study of wealthy families by private bank U.S. Trust found that only 40% of high net worth investors feel "bullishly optimistic" about the market. At the same time, 10% said they felt downright pessimistic and 12% described themselves as fearful of losing money.